Landfilling or incinerating inactivated sludge can cause secondary pollution, while the humic acid it contains can improve the physicochemical properties of soil. Tailings soil improvement and vegetation restoration areimportant measures for the ecological restoration of tailings ponds. This study explores the extraction of humic acid from inactivated sludge and its application in tailings soil improvement experiments. The results show that humic acidfrom purified inactivated sludge that has not been digested in the DN wastewater treatment plant is more suitable as a tailings modifier. Humic acid significantly increases the organic matter content in tailings soil, enhancing its fertility;1 g/L of humic acid from inactivated sludge has a notable promoting effect on plant growth. This research provides anew approach and theoretical foundation for soil-based utilization of tailings, and offers certain environmental and economic benefits.